Glaucomatous optic disc changes in the contralateral eye of unilateral normal pressure glaucoma patients

Abstract

Objective To evaluate the optic disc for structural abnormalities in the contralateral eye of unilateral normal pressure glaucoma patients. Design Cross-sectional study. Participants Fifty-three unilateral normal pressure glaucoma patients. Testing Optic disc imaging with the Heidelberg Retina Tomograph (HRT). Main outcome measures Optic disc structural parameters. Results Of the contralateral (normal visual field) eyes, 79.2% were found to have an abnormal optic disc by HRT analysis. Of the glaucomatous (abnormal visual field) eyes, 94.3% were found to have an abnormal disc. The patterns of disc abnormality were defined as marked or moderate diffuse thinning of the neuroretinal rim (NRR) or broad or narrow focal thinning of the NRR. The most common pattern in the contralateral eyes was moderate diffuse thinning of the NRR (45.2%). The most frequently abnormal segments were the nasal superior (73.8%) followed by the nasal inferior and the global NRR parameter (both 54.8%). Conclusions A high frequency of NRR thinning was found in the contralateral (normal visual field) eyes of unilateral normal pressure glaucoma patients by HRT analysis. Knowing whether these abnormalities predict future progression to the development of visual field abnormality must wait until longitudinal studies are completed. If a disc abnormality is shown to predict future field loss, then early identification will allow early treatment.